1. Field of the Invention
The present invention relates to an optical apparatus and an image-pickup apparatus including the same, and especially to a light amount adjuster and an image stabilizer of an optical apparatus.
2. Description of the Related Art
Japanese Patent Laid-open No. (“JP”) 2011-33981 discloses a configuration in which a diaphragm unit having a light amount adjusting function is disposed in front of an optical image stabilizer configured to shift a lens (an image stabilizing lens) as a part of an image-pickup optical system in a direction perpendicular to an optical axis in synchronization with an apparatus vibration. JP 2011-33981 further discloses inserting the image stabilizing lens into a space inside the diaphragm aperture, in order to make the length of the lens barrel in the optical axis direction as short as possible when it is not being used.
JP 2007-94074 discloses a light amount adjuster in which a blade having a curved shape approximated to a lens curved surface is disposed in between a first lens and a second lens, when a part of the second lens having a convex shape is inserted into a part of the first lens having a concave shape in the retracted lens barrel. In JP 2007-94074, even when the light amount adjuster is disposed in between the first lens and the second lens, a low profile in an optical axis direction may be achieved since the first lens and the second lens come closer to each other to a point where a part of the second lens sinks into a part of the first lens when the lens barrel is retracted.
JP 2011-33981 stabilizes an image by making an optical image stabilizer shift an image stabilizing lens in a direction perpendicular to the optical axis. However, a diaphragm unit having a light amount adjusting function does not shift in the direction perpendicular to the optical axis even when the image stabilizer is driven. Accordingly, when the image stabilizing lens shifts in the direction perpendicular to the optical axis, the optical axis of the image stabilizing lens shifts from the center of the diaphragm diameter. Especially, as a shift amount of the image stabilizing lens increases, a peripheral light amount decreases and the image is deteriorated.
JP 2007-94074 does not disclose a second lens adjacent to a rear side (on an image plane side) of a blade to have a function as an image stabilizing lens. However, when assuming that the second lens functions as an image stabilizing lens configured to move in the direction perpendicular to the optical axis in the image stabilization, it is difficult to sufficiently secure the clearance between the image stabilizing lens and a diaphragm blade having a curved shape approximated to the lens curved surface of the image stabilizing lens. Accordingly, an image stabilizing amount by the image stabilizing lens is limited, and a sufficient image stabilizing performance cannot be secured.